Physical chemistry is a fundamental , theoretical subject. Applied chemistry, on the other hand, is practical. Physical chemistry discusses basic hypotheses , thoughts, etc. You will want to come up with different theoretical explanations with a twist of logic. Here comes a theory. One will be extinct. Roughly one such bicycle works here. You can see the history of the atomic model. Applied chemistry, on the other hand, is how you put hypotheses , doctrines into practice. There is more to reality than theory . Examples are oil and gas exploration , exchange, distribution, etc.